A method adjusts an output power of a power supply supplying electrical power to a plasma in a plasma chamber. The method includes: connecting the power supply to at least one electrode in the plasma chamber; transporting one or more substrates relative to the electrode using a substrate carrier; maintaining the plasma by the electrical power; processing the one or more substrates with the plasma; and adjusting the output power based on a parameter related to a distance between a surface of the electrode facing a carrier-substrate-assembly and a surface of the substrate-carrier-assembly facing the electrode.